Method of making tubing



45 wherein- A lum'rlan STATES L GEORGE A. SMALL, F PHILADELPHIA.,PENNSYLVANIA, A/SSIGNOR, BY DIRECT AND 'MESNE ASSIGNMENTS, '10PHILADELPHIA BRONZE'BEABING '& TUBE COMPANY, W F PHILADELPHIA,PENNSYLVANIA, A COBPQRATION 0F: DELAWARE. L

' To all 'whom it may cof/wem.'

. Be it known that I, 'GEORGE A. SMALL, a

" citizen of the United States, residing at 4707 Windsor Ave.,Philadelphia, in the county l of Philadelphia and State of Pennsylvania,

have invented certain new Aand useful Improvements in Methods of MakingTubing,

of which the following is a specification.

This invention relates to a method of making tubing and is particularlyuseful.' in con- 7 nection with bearlng bushings of phosphor b-ronze orother suitable bearlngmetal.

One of the primary objects of my lnvention is to produce a substantiallyerfect tube from a blank in such manner t at the edges will abut andform a substantially perfect tight butt joint.

I am aware that it has been contemplated in this art to form tubes fromblanks or flatv strips but 1n s0 far as I am aware it' has hitherto beenimpossible to secure a tight with reference to bearing ushings in whichthe metal, of course, is considerablv harder than the ordinary copper orbrass tu ing and in which, also the thickne of the Wall 1s greater.

Heretofore, commerciall it has been the custom either to draw bearingbushings from' a pierced billet, the tube requiring finishing bysuitable tools, or to cast the bushings, both processes being expensiveand-wasteful A of material.

By the process hereinafter described, I lpropose to produce tubing orbushings, 1n practically any lengths-economically, expeditiously andwith no wastage of material and without the necessityl of machineiinishing.

I accomplish the foregoing,. to ether with such other objects as mayhereina r appear, by means of a method dia ammatically illustrated inthe accompanying drawings,

Figure 1 is a perspective view of the blank l l from which the-tubing isto be formed; Fig.

p eoication of Letters Patent. Patented J Application led Jl'une 22,1920. Serial No. 390,89'1.

i nn'rnon or MAKING TUBING.

(oneste-p of the forming operation gvFig. 3' is tube, preparatory todlosing the joint; Fi 6 is an end elevation of thetube with thee gessquared ready for closing up the joint; Fig.

is an enlarged fragmentary View illustrating the manner in which theedges arel squared; Fig. 8 is a cross section showing a tube in processof having its joint closed; and F ig. 9 is an enlarged fragmentary Viewcorresponding to Fig. 7, illustrating the manner in which the closing iseffected.V

In carrying out my "invention, I take a strip or blank A which may be ofany length, within practical limits, sa for example, 10 to 12 more orless, the b |ank being preferably rectangular in cross section andhaving a plus thickness and a plus width, that is to say, it is thickerthan the wall of the finished'tube and has a width greater than thecircunference of the finished tube. lThis blank is formed into a tube inany preferred manner as by means of the 'pair of forming dies B whichgive the blank a U- shape and the pair ofdies C which complete theforminof the blank into-a cylinder over a mandrel which is insertedafter the first forming operation. The tube as formed over 'the mandrelD is shown in Fig. 4:, from; in-

Agg. e, 1921.

spection of which it will be seen that the: y

edges of the metal at the joint are spaced apart and extendapproximately radially, i. e., they diverge outwardly, this beingsobecause the blank is rectangular.

As a first step essential to securing a tight butt joint, I havediscovered thatthe edges must be made substantiall parallel, and toaccomplish this I remove tlile mandrel D and pass the tube through a dieE or similar terior of the tube. Where a die is used, I construct suchdie with a smaller diameter than that of the formed tube and I havediscovered that as the tube ispassed through member adapted to performwork on the ex?- the die, the metal' at exterior, works aroundcircumferentially and tends to bring the edges into parallelism. As manypasses through dies of decreasing diamer, are

made as is necessary toubring the edges apl proximately parallel, asshown, for example, in l? ig. 6, which illustrates the tube in conditionfor the final closing operation. 'lhe manner in which the metal worksaround circumferentially during the operations whenr Work is performedon the exterior of the tube, is illustrated diagrammatically at 7 iuFig. 7. After the forming operations and the opera-tions for making theedges lparallel, the spring of the metal tends to open the joint.

For closing the joint, l pass the tube, as shown in Fig. 6 over a plug For other mem ber of similar character, and through a die G. The diameterof the plug and the die are such as to produce work both on the exteriorand the interior of the tube, so as to cause the metal to Vwhat ll termarch. rlhis arching or setting causes the joint to remain closed and,while it is somewhat problematical as to what causes this arching,

l attribute it to the performance of work .both on the inside andoutside of the tube which, l believe, has a tendency to cause the metalto flow both on the inside and the outside circumferentially and roducesan elongation suiiicient to place t e particles of the metal undercompression so that when the tube is free of the dies the spring or archof the metal is suiicient to cause the joint to remain tight. Since, asit will be readily seen, the flowing of the metal under the action oi"Ithe die and plugwill crowd the edges together, thefwhole of the closingoperation may be carried on by the die and plug, but more passes wouldbe required than if the tube is :first drawn only through the dief, asshown in Fig. 5. rllhe performance of the work by the plug and the diealso elongates the tube, and performs another function which will bepointed out.

lt is preferable that the blank should be in a soft or annealedcondition for the forming operation, and l prefer to againsoften oranneal the metal after the intermediate operations and lprior totheiinishing operation. 'lhe work performed on the tube during thefinishing operation produces the degree of hardness required in bearingbushings, and in addition, the tube, as itV leaves the finishing die andplug is ready for use, requiring no machining by tools, the die and plugserving to give the tube a high fimsh, T@ne pass over the plug F andthrough the die G is ordinarily sufcient to make the joint tight.

lit will thus be seen that li can economi-` cally, expeditiously andwithout beveling the ,edges or other wastage et material, proteeniesduce a tube from a blank with a tight joint.

rlhe tube is ready for immediate use Without ting to proper length.

l claim:

tubes which consists in. ben ing a Ametal blank to a tubular form withlongitudinal. edges in juxtaposition but not final relation and thendrawing said form so as to flow the metal and "set said edges in closerfirm abutting relation.

2. Theart of making butt joint metallic tubes which consists in bendinga metal blank to a tubular form with longitudinal edges in juxtapositionbut not in final relation and then flowing the metal of said formthroughout so as to set said edges in closer firm abutting relation.

The art of making butt joint metallic tubes which consists in forming ablank to an approximately Ulshapedv cross-section, then in bending thelimbs to form a tube with longitudinal edges in juxtaposition but not infinal relationand then in drawing the tube iowing the metal.l to setsaid edges in closer firm abutting relation.

ll. The art of making butt joint metallic tubes which consists 1nbending a metal blank to a tubular form with lon itudinal edges injuxtaposition but not in nal relation and then in flowing'the metal ofsaid form so as to set said edges in closer irm abutting relation by apressing operation i producing a wall of substantially uniformthickness.

5. The art of making butt joint metallic tubes which consists in bendinga metal blank to a tubular form with longitudinal edges in juxtapositionbut not in final relation and then in flowing the metal of said form soas to set said edges in closer firm abutting relation by a pressingoperation' producing a wall of substantially uniform thickness andhaving its, outer \and inner surfaces substantially concentric.

6. As a new article of manufacture -a butt joint tube having a wallofasusbstantially uniform thickness with inner and outer surfacessubstantially concentric, the metal of which isliiowed throughout by apressing operation to set the longitudinal edges in substantially fullyabutting relating.v

7. The art of making butt joint metallic tubes which consists in bendinga metal blank to a tubular form with longitudinal edges in juxtapositionbut not in nal relation and then flowing the metal of said form so as toset said edges in closer firm abutting relation by drawing the formthrough `a die and over a plug.

8. The art of making butt joint metallic tubes which consists 1n bendinga metal blank to a tubular ,form with longitudinal 1.. The art kot inaking butt 'ointmetallic 70 edges in juxtaposition but not in finalrelation, in making said edges approximately 10 tion, in making saidedges approximately parallel by drawing the form through a dieparallel,I and then in flowing the metal of and then in flowing themetal of said form said form throughout so as to set said edges so as toset said edges in closer firm abutting 5 in closer firm abuttinrelation. relation by a pressing operation producing 9. The art ofmaklng' butt joint metallic a Wall of substantially uniform thickness.15 tubes which consists 1n bending a metal In testimony whereof, I havehereunto blank to a'jtubular form with longitudinal signed my name.edges in juxtaposition but not in final rela- GEORGE A. SMALL.

